‘I’m checking my battery stats and it says that even though I’ve used the Facebook app for 40 minutes, it’s been doing background activites for more than two hours, costing me almost a 20% hit to the battery,’ he said.

Some suspect the reason may be down to the app recording background activity – such as tracking user’s locations, even when the background refresh setting is disabled.

Jonathan Zdziarski, an iOS developer, analysed the app and noticed some peculiar activity even when it was closed.

It *looks* like if you have location sharing enabled for Facebook, that's part of what it is doing in the background to kill your battery.